Cardiovascular disease accounts for millions of deaths around the world each year. Percutaneous coronary interventions (PCIs) are the most common coronary revascularization procedure, with over 500,000 Pas being performed in the United States alone each year. Cardiologists treat increasingly complex lesions with PCIs, including chronic total occlusions. However, conventional approaches to PCI may leave the cardiologist blind with respect to significant calcium and lipid deposits that could affect treatment.
Significant lipid or calcium deposits can affect a treatment plan for a patient undergoing PCI. For example, if a physician were aware of the extent of a lipid deposit, the physician could use a more appropriately sized stent to seal off the affected area and avoid placing the stent in a region prone to vessel dissection. In situations in which initial balloon inflation does not expand a calcified artery, the physician may apply high pressure, perform an atherectomy, or abort the procedure: all difficult decisions that would benefit from effective imaging support. Conventional imaging approaches to PCI that employ intravascular ultrasound, x-ray angiography, or fluoroscopy may show the vessel lumen, or possibly slight indications of potential calcifications. However, these approaches leave a cardiologist operating blindly with respect to the actual location, extent, and constituents of vascular lesions, especially when there is vessel remodeling.
Intravascular optical coherence tomography (IVOCT) has sufficient resolution, contrast, and penetration depth to characterize coronary artery plaques. IVOCT provides discrimination between lipid and fibrous plaque constituents, and has sufficient resolution and contrast to identify vulnerable thin cap atheromas. However, IVOCT requires extensive specialized training, which limits the number of physicians qualified to use IVOCT. Interpretation of IVOCT images is also difficult and can be time consuming. Furthermore, during a typical PCI, a single pullback may create over five hundred images, overloading the physician with data during an already stressful intervention.